Plain-English explanation of an EPA contaminant by name or code: the EPA name, whether the EPA classifies it as health-based, and how often it appears in our records. Not medical advice.
| Name | Required | Description | Default |
|---|---|---|---|
| contaminant | Yes | Contaminant name or EPA code, e.g. 'TTHM' or '2950'. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and non-destructive. The description adds the disclaimer 'Not medical advice' and outlines the return fields (EPA name, health classification, frequency), providing useful context beyond annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single concise sentence with a clear disclaimer. No extraneous words; front-loaded with the action and scope.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple read-only tool with one parameter and no output schema, the description sufficiently explains the purpose and return values. Could optionally include example output format, but not necessary for completeness.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% for the single parameter, which includes an example. The tool description adds no additional semantic detail beyond what the schema already provides, so baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it provides a 'plain-English explanation of an EPA contaminant by name or code', specifying the output includes EPA name, health classification, and frequency. No sibling tools overlap, so it is well-differentiated.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies use for understanding contaminants but does not explicitly state when not to use or mention alternatives. However, the tool is unique among siblings, so guidance is adequate.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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Some tools have overlapping purposes: search and search_cities both find cities by name, and fetch and get_city_water both retrieve detailed records for a city. However, descriptions differentiate them (e.g., search returns an id, search_cities returns counts and URL), so an agent can often pick correctly, but confusion is possible.
Tool names mix conventions: single-word verbs (fetch, search), verb_noun (compare_cities, find_cities), and noun_noun (coverage_stats). There is no consistent pattern, and similar tools have different naming styles (e.g., search vs search_cities).
10 tools is well-suited for querying EPA tap water data. Each tool serves a distinct purpose within the domain, and the count is neither too few (limiting functionality) nor too many (overwhelming).
The tool surface covers key operations: searching cities, retrieving records, comparing, filtering, explaining contaminants, and coverage stats. Minor gaps exist (e.g., no way to search contaminants by partial name), but core workflows are supported.